FIG. 12 shows the schematic configuration of a wireless communication apparatus (hereinafter called a relay station or a repeater) 123 of a related art. The relay station 123 of the related art includes a receiving antenna 41 for receiving radio wave from a not-shown transmission station, a receiving RF section 42 for high-frequency amplifying the received signal, an error correction decoding section 43 for correcting the error of the signal caused in a transmission path and decoding the signal thus corrected, hard decision sections 121 and 122 each for determining signal error with “0” and “1”, an error detection section 44 for detecting error of the signal subjected to the hard decision processing, a switching section 45 for switching the outputs of the hard decision sections 121 and 122, a re-coding section 46 for re-coding the signal outputted from the switching section 45, a transmission RF section 47 for high-frequency amplifying the re-coded signal and a transmission antenna 48 for transmitting the high-frequency signal to a not-shown receiving station.
Such the repeater 123 of the related art subjects the received signal to an error correction decoding processing (the turbo coding, the convolution coding, the LPDC coding (low density parity check coding) etc.) and then subjects the hard decision bits after the error correction decoding (a bit sequence obtained by subjecting the received signal to the error correction using the “hard decision”) to an error detection processing.
When no error is detected in this case, the bits (hard decision bits) after the error correction decoding are again subjected to the error correction coding and then relayed and transmitted. On the other hand, when any error is detected in this case, the relaying and transmission processings are not performed or the hard decision bits before the error correction decoding are relayed and transmitted.
The signal after the error correction decoding processing takes a value of “1” or “−1”. However, the signal may be converted into a bit sequence of “0” and “1” by converting the values “−1” and “1” into “1” and “0” respectively, for example. This bit sequence is called as bits after the error correction decoding and the bits after the error correction decoding are subjected to the error detection processing (see a non-patent document, for example).
Non-patent document 1: Cooperative Relaying Technique with Space Time Block Code for Multihop Communications among Single Antenna Terminals, TECHNICAL REPORT OF IEICE. WBS2003-149, A-P2003-342, RC5203-365 MoMuC2003-143, MW2003-311 (2004-03)